This invention relates to vehicular barricades, and particularly to a barricade system having a rugged extensible barricade unit for selectively and effectively preventing vehicular passage along a roadway.
In recent years there has been a dramatic increase in the incidence of terrorist attacks throughout the world. Many of these attacks are directed against governmental officials or governmental installations such as embassies. A popular terrorist tactic is to employ car bombs and suicide drivers to drive an explosive-laden vehicle near the target building and then trigger a massive explosion. Tragic examples of this type of attack are the 1983 and 1984 attacks upon the United States Embassy in Beruit, Lebanon and the 1983 attack upon the United States Marine Headquarters in Beruit.
Of course, these types of attacks could be prevented by prohibiting all vehicular traffic near the installation. Such an approach is considered unacceptable because installations such as embassies should be, and should appear to be, accessible. The image conveyed by an embassy huddled behind a labyrinth of gates and barriers is not an image that most governments desire to project. For this reason a multiplicity of gates and concrete barricades which must be negotiated like a maze are not entirely desirable. Nor, as has been unfortunately demonstrated in Beruit, are they entirely effective against a determined, suicidal terrorist attack.
One solution which would appear to be acceptable and effective would be a barricade system which would be unobtrusive, allowing unimpeded vehicular traffic to the installation, yet capable of being quickly deployed so as to absolutely prevent vehicle passage of the barricade, either by smashing through the barricade, as may be done with a gate, or by circumnavigating the barricade as may be done with cement barriers. An extensible vehicular barricade which could be placed within a roadway is one such device.
Dickinson, U.S. Pat. No. 4,354,771, discloses an above-grade curb barrier for controlling traffic which may be extended to discourage vehicular passage because of possible damage to the vehicle's tires or undercarriage, or retracted to permit vehicular passage over the barrier. Such a device would not be appropriate as an anti-terrorist barricade because it would not present a sufficient obstacle to ensure that all vehicular passage, including heavy trucks and tracked vehicles, would be stopped. Terrorists who are intent upon blowing up themselves and their truck are not likely to be deterred by the prospect of damage to their tires or undercarriage. The curb barrier is also sufficiently complex to be too expensive for such a use, especially if it were upscaled to increase the size and strength of the device.
Pop-up traffic control devices such as Roper, U.S. Pat. No. 3,963,363, Emmel, U.S. Pat. No. 3,086,430, and Bowersox, U.S. Pat. No. 3,530,775, which are installed below grade and pop up in the roadway to guide traffic do not disclose any structure or mechanism for resisting vehicular impact and preventing vehicular passage; to the contrary, they all disclose devices which are designed to yield to vehicular impact.